scholarly journals TheNextGenModel Atmosphere Grid. II. Spherically Symmetric Model Atmospheres for Giant Stars with Effective Temperatures between 3000 and 6800 K

1999 ◽  
Vol 525 (2) ◽  
pp. 871-880 ◽  
Author(s):  
Peter H. Hauschildt ◽  
France Allard ◽  
Jason Ferguson ◽  
E. Baron ◽  
David R. Alexander
Keyword(s):  
Symmetric Model ◽  
Spherically Symmetric ◽  
Giant Stars ◽  
Effective Temperatures ◽  
Spherically Symmetric Model

scholarly journals Comparison of Blanketing in a 3000 K, Oxygen Rich, Spherically Symmetric Model with the Blanketing in Non-Mira, M Giant Stars

1989 ◽  
Vol 106 ◽  
pp. 157-157
Author(s):  
G.C. Augason ◽  
J.A. Brown ◽  
D.R. Alexander
Keyword(s):  
Water Vapor ◽  
Model Parameters ◽  
Symmetric Model ◽  
Spherically Symmetric ◽  
Giant Stars ◽  
Symmetrical Model ◽  
Equilibrium Data ◽  
Spherically Symmetric Model ◽  
The Continuum ◽  
Flux Curve

A flux curve has been computed using a preliminary, spherically symmetric model for a 3000 K, oxygen rich, giant star. The model was computed using the opacity sampling method with an improved frequency set, improved molecular equilibrium data and an improved set of opacities. In addition, a continuum flux curve is computed using the same model and only continuum opacity sources. The relative and to some extent the absolute blanketing used to compute both the model and the flux curve derived from the model may be illustrated by dividing the normal flux curve by the continuum flux curve. This same procedure is used to illustrate the blanketing in an observed star by dividing the observed flux curve by the continuum flux curve. When this is done, the blanketing in an observed flux curve may be compared with the blanketing in a model. When this comparison is made, it is obvious that the treatment of blanketing in the “new” flux curve, computed using the spherically symmetric model and using new parameters, is superior to the flux curves based on earlier models. This is especially true in the regions of the fundamental, the first overtone and the second overtone of Co. Also, the new water vapor opacity is much improved. The new water vapor opacity is based on actual measurements of high temperature water vapor. Correct representation of water vapor opacity is extremely important for oxygen rich stars because it forms a psuedo continuum because of its many lines. The TiO opacity does not fit the observations well. When the spherically symmetrical model flux curve is compared directly to an observed flux curve, the new flux curve gives a better fit than do flux curves computed from previous models. There is still (at least for the non-Mira stars) a serious flux excess in the model flux curves at 1.6 microns in the region of the H minus b-f and f-f crossover. However, this excess is not as great for the spherically symmetric model as it is for earlier plane parallel models. It is not determined if this improvement is due to spherical symmetry or due to the new model parameters.

MØLLER ENERGY–MOMENTUM COMPLEX FOR HIGHER-DIMENSIONAL SPHERICALLY SYMMETRIC SPACETIME IN GENERAL RELATIVITY

2012 ◽  
Vol 27 (40) ◽  
pp. 1250231 ◽  
Author(s):  
HÜSNÜ BAYSAL
Keyword(s):  
General Relativity ◽  
Momentum Density ◽  
Momentum Tensor ◽  
Symmetric Model ◽  
Spherically Symmetric ◽  
Higher Dimensional ◽  
Energy And Momentum ◽  
Momentum Complex ◽  
Spherically Symmetric Metric ◽  
Spherically Symmetric Model

We have calculated the total energy–momentum distribution associated with (n+2)-dimensional spherically symmetric model of the universe by using the Møller energy–momentum definition in general relativity (GR). We have found that components of Møller energy and momentum tensor for given spacetimes are different from zero. Also, we are able to get energy and momentum density of various well-known wormholes and black hole models by using the (n+2)-dimensional spherically symmetric metric. Also, our results have been discussed and compared with the results for four-dimensional spacetimes in literature.

scholarly journals Relativistic Zel’dovich approximation in a spherically symmetric model

1998 ◽  
Vol 57 (10) ◽  
pp. 6094-6103 ◽  
Author(s):  
Masaaki Morita ◽  
Kouji Nakamura ◽  
Masumi Kasai
Keyword(s):  
Symmetric Model ◽  
Spherically Symmetric ◽  
Spherically Symmetric Model

Separation of gas and dust in the winds of AGB stars

2018 ◽  
Vol 14 (S343) ◽  
pp. 462-463
Author(s):  
Lars Mattsson ◽  
Christer Sandin ◽  
Paolo Ventura
Keyword(s):  
High Resolution ◽  
Asymptotic Giant Branch ◽  
Radiation Hydrodynamics ◽  
Symmetric Model ◽  
Spherically Symmetric ◽  
Agb Stars ◽  
First Results ◽  
Forced Turbulence ◽  
Spherically Symmetric Model ◽  
Entire Picture

AbstractWe present first results from a project aiming at a better understanding of how gas and dust interact in dust-driven winds from Asymptotic Giant Branch (AGB) stars. We are at the final stage of developing a new parallelised radiation-hydrodynamics (RHD) code for AGB-wind modelling including a new generalised implementation of drift. We also discuss first results from high-resolution box simulations of forced turbulence intended to give quantitative “3D corrections” to dust-driven winds from AGB stars. It is argued that modelling of dust-driven winds of AGB stars is a problem that may need to be treated in a less holistic way, where some parts of the problem are treated separately in detailed simulations and are parameterised back into a less detailed (1D spherically symmetric) model describing the entire picture.

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